blobmsg.c

   1 /*
   2  * Copyright (C) 2010-2012 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 #include "blobmsg.h"
  17
  18 static const int blob_type[__BLOBMSG_TYPE_LAST] = {
  19         [BLOBMSG_TYPE_INT8] = BLOB_ATTR_INT8,
  20         [BLOBMSG_TYPE_INT16] = BLOB_ATTR_INT16,
  21         [BLOBMSG_TYPE_INT32] = BLOB_ATTR_INT32,
  22         [BLOBMSG_TYPE_INT64] = BLOB_ATTR_INT64,
  23         [BLOBMSG_TYPE_STRING] = BLOB_ATTR_STRING,
  24         [BLOBMSG_TYPE_UNSPEC] = BLOB_ATTR_BINARY,
  25 };
  26
  27 static uint16_t
  28 blobmsg_namelen(const struct blobmsg_hdr *hdr)
  29 {
  30         return be16_to_cpu(hdr->namelen);
  31 }
  32
  33 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
  34 {
  35         const struct blobmsg_hdr *hdr;
  36         const char *data;
  37         int id, len;
  38
  39         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
  40                 return false;
  41
  42         hdr = (void *) attr->data;
  43         if (!hdr->namelen && name)
  44                 return false;
  45
  46         if (blobmsg_namelen(hdr) > blob_len(attr) - sizeof(struct blobmsg_hdr))
  47                 return false;
  48
  49         if (hdr->name[blobmsg_namelen(hdr)] != 0)
  50                 return false;
  51
  52         id = blob_id(attr);
  53         len = blobmsg_data_len(attr);
  54         data = blobmsg_data(attr);
  55
  56         if (id > BLOBMSG_TYPE_LAST)
  57                 return false;
  58
  59         if (!blob_type[id])
  60                 return true;
  61
  62         return blob_check_type(data, len, blob_type[id]);
  63 }
  64
  65 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type)
  66 {
  67         struct blob_attr *cur;
  68         bool name;
  69         int rem;
  70
  71         switch (blobmsg_type(attr)) {
  72         case BLOBMSG_TYPE_TABLE:
  73                 name = true;
  74                 break;
  75         case BLOBMSG_TYPE_ARRAY:
  76                 name = false;
  77                 break;
  78         default:
  79                 return false;
  80         }
  81
  82         blobmsg_for_each_attr(cur, attr, rem) {
  83                 if (blobmsg_type(cur) != type)
  84                         return false;
  85
  86                 if (!blobmsg_check_attr(cur, name))
  87                         return false;
  88         }
  89
  90         return true;
  91 }
  92
  93 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
  94                         struct blob_attr **tb, void *data, int len)
  95 {
  96         struct blob_attr *attr;
  97         int i = 0;
  98
  99         memset(tb, 0, policy_len * sizeof(*tb));
 100         __blob_for_each_attr(attr, data, len) {
 101                 if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 102                     blob_id(attr) != policy[i].type)
 103                         continue;
 104
 105                 if (!blobmsg_check_attr(attr, false))
 106                         return -1;
 107
 108                 if (tb[i])
 109                         continue;
 110
 111                 tb[i++] = attr;
 112                 if (i == policy_len)
 113                         break;
 114         }
 115
 116         return 0;
 117 }
 118
 119
 120 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 121                   struct blob_attr **tb, void *data, int len)
 122 {
 123         struct blobmsg_hdr *hdr;
 124         struct blob_attr *attr;
 125         uint8_t *pslen;
 126         int i;
 127
 128         memset(tb, 0, policy_len * sizeof(*tb));
 129         pslen = alloca(policy_len);
 130         for (i = 0; i < policy_len; i++) {
 131                 if (!policy[i].name)
 132                         continue;
 133
 134                 pslen[i] = strlen(policy[i].name);
 135         }
 136
 137         __blob_for_each_attr(attr, data, len) {
 138                 hdr = blob_data(attr);
 139                 for (i = 0; i < policy_len; i++) {
 140                         if (!policy[i].name)
 141                                 continue;
 142
 143                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 144                             blob_id(attr) != policy[i].type)
 145                                 continue;
 146
 147                         if (blobmsg_namelen(hdr) != pslen[i])
 148                                 continue;
 149
 150                         if (!blobmsg_check_attr(attr, true))
 151                                 return -1;
 152
 153                         if (tb[i])
 154                                 continue;
 155
 156                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 157                                 continue;
 158
 159                         tb[i] = attr;
 160                 }
 161         }
 162
 163         return 0;
 164 }
 165
 166
 167 static struct blob_attr *
 168 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 169 {
 170         struct blob_attr *attr;
 171         struct blobmsg_hdr *hdr;
 172         int attrlen, namelen;
 173         char *pad_start, *pad_end;
 174
 175         if (!name)
 176                 name = "";
 177
 178         namelen = strlen(name);
 179         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 180         attr = blob_new(buf, type, attrlen);
 181         if (!attr)
 182                 return NULL;
 183
 184         hdr = blob_data(attr);
 185         hdr->namelen = cpu_to_be16(namelen);
 186         strcpy((char *) hdr->name, (const char *)name);
 187         pad_end = *data = blobmsg_data(attr);
 188         pad_start = (char *) &hdr->name[namelen];
 189         if (pad_start < pad_end)
 190                 memset(pad_start, 0, pad_end - pad_start);
 191
 192         return attr;
 193 }
 194
 195 static inline int
 196 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 197 {
 198         return (char *)attr - (char *) buf->buf;
 199 }
 200
 201
 202 void *
 203 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 204 {
 205         struct blob_attr *head = buf->head;
 206         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 207         unsigned long offset = attr_to_offset(buf, buf->head);
 208         void *data;
 209
 210         if (!name)
 211                 name = "";
 212
 213         head = blobmsg_new(buf, type, name, 0, &data);
 214         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 215         buf->head = head;
 216         return (void *)offset;
 217 }
 218
 219 void *
 220 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, int maxlen)
 221 {
 222         struct blob_attr *attr;
 223         void *data_dest;
 224
 225         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 226         if (!attr)
 227                 return NULL;
 228
 229         data_dest = blobmsg_data(attr);
 230         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 231         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 232
 233         return data_dest;
 234 }
 235
 236 void
 237 blobmsg_add_string_buffer(struct blob_buf *buf)
 238 {
 239         struct blob_attr *attr;
 240         int len, attrlen;
 241
 242         attr = blob_next(buf->head);
 243         len = strlen(blobmsg_data(attr)) + 1;
 244
 245         attrlen = blob_raw_len(attr) + len;
 246         blob_set_raw_len(attr, attrlen);
 247         blob_fill_pad(attr);
 248
 249         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 250 }
 251
 252 int
 253 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 254                   const void *data, int len)
 255 {
 256         struct blob_attr *attr;
 257         void *data_dest;
 258
 259         attr = blobmsg_new(buf, type, name, len, &data_dest);
 260         if (!attr)
 261                 return -1;
 262
 263         if (len > 0)
 264                 memcpy(data_dest, data, len);
 265
 266         return 0;
 267 }